EP0012293B1 - Cyanoethylated polyamide amines as hardeners for polyepoxides - Google Patents

Description

The invention relates to new curing agents for 1,2-polyepoxides with more than one 1,2-epoxy group per molecule from reaction products of lactams with pentaethylene hexamine and acrylonitrile and / or methacrylonitrile.

It is known to react aliphatic primary and / or secondary di- or polyamines with z-caprolactam to polyamides having amino groups, preferably at least two amide groups and two primary amine groups-containing polyamides, and to use the reaction products obtained as hardeners for polyepoxy resins (cf. AS 1 124 688 = U.S. Patent 3,036,975). As can be seen from the cited documents, the (e-caprolactam) polyamide amines are liquid or solid compounds. The liquid products, mixed with conventional liquid polyepoxy resins, for. B. based on bisphenol A (epoxy equivalent 175-210) can be used as casting resins and harden in a 40 g batch within 40 minutes without the addition of heat. In order to achieve good heat resistance and chemical resistance, moldings made from these mixtures have to be post-tempered for several hours at temperatures of 120-150 ° C. A major disadvantage of such mixtures is that, despite their high reactivity, they cannot be used as coating agents which cure at room temperature, since films cured at room temperature remain dull and tacky. Mixtures prepared from liquid amidanes and solid (higher molecular weight) bisphenol A epoxy resin, dissolved in a solvent, can only be used as coating agents which can be baked at about 120 ° C., according to Example 11 of this document. The same applies to the solid polyamide amines from e-caprolactam. The documents also show that curing products made from epoxy resins and polyamide amines based on e-caprolactam + polyamine have poorer heat resistance and higher chemical resistance than corresponding products with polyamide amines based on dimerized fatty acids and polyamines.

It is also known to use primary and / or secondary di- and / or polyamines, e.g. B. ethylenediamine, tetraethylene pentamine, etc., to react with acrylonitrile to cyanoethylated di- and polyamines (cf. DE-AS 1 034 856 = US Pat. No. 2,753,323) and the reaction products obtained as hardeners for polyepoxides with more than one 1,2- Use epoxy group per molecule. A major advantage of the cyanoethylated amines is that, compared to the starting amines, they have a reduced reactivity towards epoxy compounds and thus have a longer pot life. that is, the time between the time of adding the curing agent to the polyepoxide and the time at which the polyepoxide / hardener mixture can no longer be processed is increased. The lower the reactivity, the greater the more the original amine hydrogen atoms have been cyanoethylated. For the production of large-volume molded articles from polyepoxides, cyanoethylated polyamines can be used with advantage, but curing takes place at elevated temperatures to achieve good mechanical and electrical properties. A serious disadvantage, however, is the fact that cyanoethylated polyamines do not harden sufficiently as a result of atmospheric influences when curing polyepoxides at room temperature, especially in thin layers, so that unsightly and sticky surfaces are obtained even after many days of curing. The same applies to the unmodified starting amines, which, when cured with thin layers of polyepoxides at room temperature, despite their often high reactivity, have greasy and bluish tarnishing even after a very long curing time. Furthermore, it is known from US Pat. No. 3,091,595 to produce polyamide amines from dimerized fatty acids and polyamines and to convert all or part of the amino hydrogen atoms still present with acrylonitrile to cyanoethylated polyamide amines. Neither the polyamide amines from dimerized fatty acids and polyamines nor the acrylonitrile-modified polyamide amines from dimerized fatty acids and polyamines harden with polyepoxides in a thin layer at room temperature within 24 hours to form clear, hard, tack-free films with a trouble-free surface, as in Example 1 of the US Pat 3,091,595 and the comparative experiments in the present application.

worin

• m = 0-10
• R und/oder R' unverzweigte und verzweigte Alkylenreste mit 2 bis 40 C-Atomen bedeuten, und Lactamen und (Meth)Acrylnitril hergestellt werden. Zwar fällt unter die größe Zahl der vorstehend formelmäßig angegebenen Polyamine auch Pentaethylenhexamin, jedoch läßt sich der genannten Offenelgungsschrift weder entnehmen, noch wird durch sie nahegelegt, daß cyanethylierte Polyamidamine auf Basis von Pentaethylenhexamin und Polyepoxide mit mindestens einer 1,2-Epoxidgruppe Härtungsprodukte ergeben, die unerwartete Vorteile aufweisen und eine erfinderische Tätigkeit begründen lassen.

Finally, DE-OS 2 164 099 curing agents for polyepoxides with more than one 1,2-epoxy group are known, which from polyamines of the general formula

wherein

• m = 0-10
• R and / or R 'are unbranched and branched alkylene radicals having 2 to 40 carbon atoms, and lactams and (meth) acrylonitrile are prepared. Although pentaethylenehexamine also falls under the large number of polyamines given in the formula above, it cannot be deduced from the above-mentioned publication, nor does it suggest that cyanoethylated polyamidamines based on pentaethylenehexamine and polyepoxides with at least one 1,2-epoxy group give hardening products which have unexpected advantages and justify inventive step.

The subject of the invention are therefore

• A. 1 Mol eines Polyamins der Formel
  
  worin p = 0, n = 2 oder 3, m = 0 bis 6, X = NH₂ bzw.
  p = 1, n = 2 oder 3, m = 0 und X = H bedeuten ;
• B. 0,5-2,3 Mol eines gesättigten Lactams, und
• C. 0,4-2,8 Mol Acrylnitril, Methacrylnitril oder deren Mischungen dadurch gekennzeichnet, daß das Polyamin Pentaethylenhexamin ist.

Hardening agent for polyepoxides with more than one 1,2-epoxy group per molecule based on cyanoethylated polyamide amines from polyadditive units of

• A. 1 mole of a polyamine of the formula
  
  where p = 0, n = 2 or 3, m = 0 to 6, X = NH ₂ or
  p = 1, n = 2 or 3, m = 0 and X = H;
• B. 0.5-2.3 mol of a saturated lactam, and
• C. 0.4-2.8 mol acrylonitrile, methacrylonitrile or mixtures thereof, characterized in that the polyamine is pentaethylene hexamine.

worin

• Y für eine CH-Gruppe steht, wobei dann
• R Wasserstoff und
• a eine ganze Zahl von Null bis 9 bedeutet, oder
• Y für ein Stickstoffatom steht, wobei dann
• R einen gesättigten aliphatischen Rest, vorzugsweise Methyl, einen araliphatischen Rest mit 7-12 Kohlenstoffatomen oder einen Pyridinrest oder einen durch niedere Alkylreste (C₁-C₄) substituierten Pyridinrest und
• a die Zahl 3 bedeuten.

Suitable saturated lactams are those of the formula below or mixtures thereof:

wherein

• Y represents a CH group, where then
• R is hydrogen and
• a is an integer from zero to 9, or
• Y stands for a nitrogen atom, where then
• R is a saturated aliphatic radical, preferably methyl, an araliphatic radical with 7-12 carbon atoms or a pyridine radical or a pyridine radical substituted by lower alkyl radicals (C ₁ -C ₄ ) and
• a is the number 3.

Preferred lactams are γ-butyrolactam, 8-valerolactam, s-caprolactam, laurolactam, in particular e-caprolactam. Instead of the lactams, the aminocarboxylic acids on which the lactams are based can also be used to prepare the amidamines.

Instead of acrylonitrile, methacrylonitrile or mixtures of acrylonitrile and methacrylonitrile can also be used. Acrylonitrile is preferred.

The cyanoethylated polyamide amines are prepared under known process conditions. The lactams or aminocarboxylic acids are reacted with the polyalkene polyamines at temperatures between 120 and 300 ° C., preferably 150-280 ° C., in particular at 150-250 ° C. The addition or condensation can be purely thermal or acid-catalyzed. Based on lactam or aminocarboxylic acid, the catalysts used are between 0.01-1% by weight of an inorganic or organic strong acid such as phosphoric acid, phosphorous acid, sulfuric acid, hydrochloric acid, phenylphosphonic acid, benzene or toluenesulfonic acid. The reaction time varies between about 30 minutes and several hours and is chosen so that the conversion is as complete as possible. Unreacted starting materials can be removed by distillation. However, this is generally not necessary. One advantage of the products according to the invention is u. a. in that unconverted fractions up to a total of 40% by weight, based on the starting materials, can remain in the reaction mixture without the properties changing significantly. The molar ratio of the reactants used normally corresponds to the molar ratio desired in the polyamide amine, ie 0.5-2.3 mol of lactam or amino acid per mol of polyamine. However, it can also be larger or smaller. However, the excess starting material must then be at least partially removed before further reaction.

The addition of acrylonitrile or methacrylonitrile or mixtures thereof takes place at 10 to 180 ° C, preferably at 20-140 ° C, in particular at 30-120 ° C. The nitriles are used in such an amount as is to be contained in the desired end product, ie 0.4-2.8 moles per mole of polyamine. Since the addition reaction is generally exothermic, (meth) acrylonitrile is expediently metered into the reaction products of the lactam or amino acids with the polyamines in accordance with the amount of heat to be removed.

The curing agents according to the invention are liquids which can be mixed with up to 20% by weight of a suitable thinner such as benzyl alcohol to further reduce the viscosity. The curing agents have amine equivalents (= NH equivalent) of 60 to 120, amine equivalent being understood as the quotient of the molecular weight of the product and the number of hydrogen atoms bonded to amine nitrogen. Hydrogen atoms bound to carbonylamino groups (-CO-NH-) are excluded.

The curing agents according to the invention can be used not only as usual aliphatic polyamines or polyamide amines for curing polyepoxides in the heat or in large layer thicknesses at room temperature, but also - and this is the surprising advantage over comparable amine-based hardeners - for curing polyepoxides in thin layers (less than 0.5 cm) at room temperature, whereby tack-free, dust-dry, clear, glossy films and coatings with a perfect surface are obtained within 24 hours.

0.6 to 1.5, preferably 0.8 to 1.2, amine equivalents (= NH equivalents) of the curing agents according to the invention can be used for curing per epoxy equivalent.

The epoxy equivalent is understood to mean the amount of 1,2-epoxy compound in which a 1,2-epoxy group is contained. Accordingly, the epoxy value represents the number of 1,2-epoxy groups contained in 100 g of epoxy compound.

The known, customary polyepoxides with more than one 1,2-epoxy group are suitable as epoxides. These include polyglycidyl ethers of polyhydric phenols, e.g. from pyrocatechol, resorcinol, hydroquinone, from 4,4'-dihydroxydiphenylmethane, from 4,4'-dihydroxy-3,3'-dimethyldiphenylmethane, from 4,4'-dihydroxydiphenyidimethyimethane (bisphenol A), from 4,4'-dihydroxydiphenylmethyl methane, from 4,4'-dihydroxydiphenylcyclohexane, from 4,4'-dihydroxy-3,3'-dimethyldiphenylpropane, from 4,4'-dihydroxydiphenyl, from 4,4'- Dihydroxydiphenyl sulfone, from tris (4-hydroxyphenyl) methane, from the chlorination and bromination products of the above-mentioned diphenols, in particular from bisphenol A; from novolaks (ie from reaction products of mono- or polyhydric phenols with aldehydes, in particular formaldehyde, in the presence of acidic catalysts), from diphenols obtained by esterifying 2 mol of the sodium salt of an aromatic oxicarboxylic acid with one mol of a dihaloalkane or dihalodialkyl ether (cf. British Patent 1017612), from polyphenols obtained by the condensation of phenols and long-chain halogen paraffins containing at least 2 halogen atoms (cf. British Patent 1,024,288).

In addition to the epoxy resins based on a polyhydric phenol and a chloro-epoxy compound, the epoxidized ring compounds according to US Pat. No. 2,716,123 can also be used.

Glycidyl ethers of polyhydric alcohols, for example from 1,4-butanediol, 1,4-butenediol, glycerol, trimethylolpropane, pentaerythritol and polyethylene glycols, may also be mentioned.

Of further interest are triglycidyl isocyanurate, N, N'-diepoxypropyloxamide, polyglycidyl thioether from polyvalent thiols, such as, for example, from bismercaptomethylbenzene, diglycidyltrimethylene trisulfone, epoxidized polybutadiene, epoxidized linseed oil, vinylcyclohexene diepoxide.

worin A einen mindestens 2-wertigen Rest eines gegebenenfalls durch Sauerstoff und/oder cycloaliphatische Ringe unterbrochenen, aliphatischen Kohlenwasserstoffs oder den 2-wertigen Rest eines cycloaliphatischen Kohlenwasserstoffs, R Wasserstoff oder Alkylreste mit 1-3 C-Atomen und n eine Zahl zwischen 2 bis 6 bedeuten, oder Mischungen von Glycidylcarbonsäureestern der angegebenen allgemeinen Formel (vgl. britische Patentschrift 1 220 702).Also suitable are: Glycidyl esters of polyvalent aromatic, aliphatic and cycloaliphatic carboxylic acids, for example diglycidyl phthalate, diglycidyl terephthalate, diglycidyl tetrahydrophthalate, diglycidyl adidate and methylated hexanoic acid; 2 moles of a diol or 1 / n mole of a polyol with n hydroxyl groups, such as glycidyl carboxylic acid esters of the general formula

in which A is an at least divalent radical of an aliphatic hydrocarbon which may be interrupted by oxygen and / or cycloaliphatic rings or the divalent radical of a cycloaliphatic hydrocarbon, R is hydrogen or alkyl radicals having 1-3 C atoms and n is a number between 2 and 6 mean, or mixtures of glycidyl carboxylic acid esters of the indicated general formula (cf. British Patent 1,220,702).

Also of interest are epoxy resins which have been reacted with monocarboxylic acids, in particular with fatty acids, such as those from linseed oil, sunflower oil, tall oil, wainnut oil, dehydrated castor oil, herring oil and the like. The epoxy resins can be esterified in a simple manner by refluxing them in the presence of one or more carboxylic acids and at the same time removing the water azeotropically.

Polyglycidyl ethers of polyhydric phenols and polyhydric alcohols and glycidyl esters, in particular polyepoxides based on bisphenol A, are preferred.

The resin compositions consisting of hardener and epoxy components can additionally contain extenders such as coumarone oil, diluents such as dibutyl phthalate, if they are preferably used without them, as well as reactive diluents such as monoglycide esters or monoglycidyl ethers such as reaction products of phenols with epichlorohydrin, catalysts which accelerate curing, such as alcohols, phenols , tert. Amines or organic acids such as salicylic acid and amines, acids such as BF ₃ or its Adducts with alcohols, phosphorus compounds such as triphenylphosphite, retarders that delay hardening, such as ketones or esters, and finally solid additives, fillers and reinforcing materials such as talc, quartz powder, titanium dioxide, diatomaceous earth, heavy spar, asbestos, glass fibers, zinc dust, mica, siccatives, tixotropic agents and dye pigments such as iron oxide, chromium oxide and cadmium sulfide. UV stabilizers can also be added for outdoor use.

The systems described are used with particular advantage where cold-curing epoxy resins are generally used, for. B. for the production of castings and resin mats, but especially in the coating and painting sector.

Metals, wood, paper, cardboard, textiles, leather, glass, plastics, ceramic materials and the like come as substrates to be coated or coated. a. in question.

The parts and percentages given in the examples relate to the weight, unless stated otherwise.

The reactivity shown in the tables is determined by using 100 of the resin / hardener mixture specified, using polyepoxide and amine hardener in equivalent amounts (1 epoxy equivalent = 1 NH equivalent), in a 250 ml beaker at room temperature (approx 23 ° C) leaves itself and detects the temperature rise. The temperature reached after 20 minutes is given in the table and represents a measure of the reactivity of the resin / hardener mixture and also for the hardener. If the temperature exceeds 50 ° C within 20 minutes, the service life is too short. Such a mixture can also not be formed into compact, perfect moldings with a large layer thickness (> several cm), since the reaction mixture can overheat as a result of the exothermic reaction, which can lead to charring of the casting.

The run-off viscosities given in the examples were measured in accordance with DIN 53 211 in a 6 mm run-out cup.

Epoxy resin I listed in the tables is a bisphenol A diglycidyl ether with an epoxy value of 0.55. Epoxy resin 11 is a mixture of epoxy resin I (70 parts by weight) and 30 parts by weight of tert-butylphenylglycidyl ether, the tert-butylphenol ether used to prepare the tert-butylphenylglycidyl ether being a technical mixture of ortho- and parate. -Butylphenol is. The tert-butylphenol is reacted in a known manner with epichlorohydrin in the presence of sodium hydroxide solution to give glycidyl ether. The epoxy value of the epoxy resin 11 is 0.5.

The film properties specified in the tables were measured on films made from the specified epoxy / hardener mixture after application in a 0.3 to 0.5 mm thick layer on glass plates after drying for 24 hours at room temperature (approx. 23 ° C.) were obtained. Epoxy resin and hardener were used in an equivalent ratio.

The films were assessed according to the following criteria: freedom from tack, gloss, hardness (scratch resistance), surface defects (= blooming effect, wavy defects, orange peel effect) and transparency.

The first requirement for the suitability of an epoxy resin at room temperature is of course the non-stickiness of the film (surface), which was determined as follows:

The underlay is placed with the lacquer layer upwards on a tared scale, which is loaded with a counterweight of 1 kg. A small, fat-free cotton ball of 2 to 3 cm in diameter is placed on the lacquer layer and a small metal disc with a diameter of 2 cm is placed on top of it. Now press the disk with your finger until the balance is in equilibrium, and the balance is kept in balance for 10 seconds. After removing the metal disc, an attempt is made to remove the cotton ball by blowing gently. The varnish layer is tack-free when the bulk no longer sticks to the varnish layer and no hairs remain.

The scratch resistance of a surface is determined using the pencil hardness, whereby the following assignment applies:

example 1

a) A mixture of 1,392 g (6 mol) of pentaethylene hexamine (molecular weight 232) and 678 g (6 mol) of e-caprolactam (molecular weight 113) are boiled under nitrogen and stirred at a bottom temperature of 215-221 ° C. for 10 h Vacuum freed from unreacted starting materials. A fraction (123-170 ° C / 1.599-0.933 mbar (1.2-0.7 Torr), 184 g) is obtained, which essentially consists of e-caprolactam and a fraction (182-202 ° C / 0.799 mbar (0.6 Torr), 430 g), which mainly consists of pentaethylene hexamine. Both fractions can be used again as starting material in a subsequent batch.

The residue of the distillation, the reaction product of e-caprolactam and pentaethylene hexamine = 1,355 g, is a yellowish oil. It has an outlet viscosity of 2'30 "(= 2 minutes 30 seconds) in a 6 mm DIN beaker and an NH equivalent of 44. Films obtained from the above polyamide amine and epoxy resins I and II at room temperature after curing for 24 hours have the properties shown in Table 1 under 1a (comparison).

b) The reaction product of s-caprolactam and pentaethylene hexamine (according to Example la) (1 355 g) is reacted at 50-60 ° C within 2 hours with stirring with 412 g (7.8 mol) of acrylonitrile. This gives 1,756 g of a cyanoethylated polyamidamine according to the invention, which is a viscous yellowish oil with an outlet viscosity of 4'20 "and an NH equivalent of 84. Films obtained from the above cyanethylated polyamidamine and epoxy resins I and II at room temperature after curing for 24 hours the properties evident from Table 1 under 1b (invention).

c) For comparison with the hardener 1b according to the invention, pentaethylene hexamine (NH equivalent 29, outlet viscosity in a 6 mm DIN cup 13 seconds) and epoxy resin I or 11 were mixed in an equivalent ratio and films were drawn on glass plates. After curing for 24 hours at room temperature, the film properties shown in the table under 1c were obtained.

d) For further comparison, 232 g (1 mol) of pentaethylene hexamine were reacted at 106 ° C. with 106 g (2 mol) of acrylonitrile with stirring in 1 hour. A yellowish oil with an outlet viscosity of 1 minute and an NH equivalent of 56 is obtained. Films obtained from this amine and epoxy resins I and II at room temperature after curing for 24 hours have the properties shown in the table under 1d (comparison).

e) Furthermore, a cyanoethylated polyamide amine from soybean oil fatty acid, diethylene triamine and acrylonitrile according to Example 1 of US Pat. No. 3,091,595, (NH equivalent 200, an outlet viscosity in a 6 mm DIN cup could no longer be measured) with epoxy resin I im equivalent ratio mixed. Films were drawn on glass plates and the film properties were tested after curing for 24 hours at room temperature. See table 1 under 1e (comparison).

f) According to Example 1 of US Pat. No. 3,091,595, cyanoethylated polyamide amine was prepared in which the diethylene triamine is replaced by pentaethylene hexamine. NH equivalent 127; an outlet viscosity in the 6 mm DIN cup could no longer be measured. Films obtained from this cyanoethylated amidamine and epoxy resin I at room temperature after curing for 24 hours have the properties shown in Table 1 under 1f (comparison).

Example 2

a) A mixture of 4 176 g (18 mol) of pentaethylene hexamine and 2 034 g (18 mol) of caprolactam is boiled for 10 hours under nitrogen and with stirring. The bottom temperature is 214-220 ° C. Then a conversion of 80-83%, based on the polyamine used, is achieved. In all of the examples below, sales are always based on the polyamine used. b) 1 190 g of this reaction product are mixed at 50-60 ° C with stirring within 1 hour with 372 g (6.9 mol) of acrylonitrile and stirred at 50-60 ° C for half an hour. The amine according to the invention, a yellow oil, has an NH equivalent of 72 and an outlet viscosity in the 6 mm DIN cup of 2'3 ". The films obtained from this amine and epoxy resins I and II at room temperature after 24 hours have the Properties evident from Table 1 under 2b (invention).

Example 3

A mixture of 1296 g (5.55 mol) of pentaethylene hexamine, 626 g (5.55 mol) of caprolactam and 5.8 g of p-toluenesulfonic acid is heated for 5 hours at 190 ° C. with nitrogen and stirring. The turnover is then 92%.

The pale yellow oil obtained is then mixed at 50-60 ° C. with stirring in 2 hours with 600 g (11.3 mol) of acrylonitrile and kept for a further half hour under these reaction conditions. The outlet viscosity (6 mm DIN cup) is 2'3 "and the NH equivalent is 74. Films obtained from this amine and epoxy resins I and II at room temperature after a curing time of 24 hours have the films in Table 1 under 3 (invention) specified properties.

Example 4

1,355 g of the polyamide amine obtained according to Example la are reacted with 312 g (5.9 mol) of acrylonitrile under the conditions of Example 1b. A yellowish oil is obtained which has an NH equivalent of 71 and an outlet viscosity (6 mm DIN cup) of 3 '. Films obtained from this amine and epoxy resins I and 11 at room temperature after a curing time of 24 hours have the properties indicated in the table under 4 (invention).

Example 5

A mixture of 696 g (3 mol) of pentaethylene hexamine and 339 g (3 mol) of caprolactam is boiled under reflux for 12 hours, the bottom temperature being 221-235 ° C. Turnover: approx. 85-87%. 345 g (1 mol) of the polyamide amine obtained are reacted with 79.5 g (1.5 mol) of acrylonitrile as in Example 1b). A yellowish oil with an outlet viscosity of 4'30 "(6 mm DIN cup) and an NH equivalent of 66 is obtained. Films obtained from this amine and epoxy resins 1 and II at room temperature after a curing time of 24 hours have the films shown in Figs Table given under 5 (invention) properties.

A comparison of the evaluation of the properties listed in Table 1 shows that cyanethylated polyamide amines and polyepoxides according to the invention in thin layers after 24 hours of curing give glossy, clear films with tack-free film surfaces without or with only minor defects, which in most cases are scratch-resistant . In contrast, with the corresponding non-cyanoethylated polyamide amines (Example 1a), or with the polyamine used to prepare the polyamide amine (Example 1c) or the corresponding cyanethylated polyamine (Example 1d), or with cyanethylated polyamide amiria according to US Pat. No. 3,091,595 (Examples 1e and 1f) after 24 hours of curing at room temperature, obtain films which have no tack-free and scratch-resistant surfaces. In most cases, the comparison films have surfaces with strong disturbances and are cloudy. These results are all the more surprising since in most cases the comparison hardeners have a higher reactivity.

Even if the curing agents according to the invention contain unreacted starting products (Examples 2b, 3 and 5), mixed with polyepoxides, they give glossy, tack-free, clear films without or with very little surface defects after a curing time of 24 hours. In example 4, the curing agent according to the invention is used in which the degree of cyanoethylation has been varied.

Example 6

a) A mixture of 232 g (1 mol) of pentaethylene hexamine, 203 g (1.8 mol) of caprolactam and 1.3 g of p-toluenesulfonic acid is stirred at 180 ° C. under nitrogen for 8-10 hours. The result is a yellowish oil with an outlet viscosity in the 6 mm DIN cup of 4'20 "and an NH equivalent of 54.

The film properties can be found in Table 2 under 6a (comparison).

Turnover: approx. 71%.

b) 435 g of the product according to 8a are reacted quantitatively at 50-60 ° C. with 80 g (1.51 mol) of acrylonitrile. The yellowish oil obtained has an NH equivalent of 79 and an outlet viscosity in a 6 mm DIN cup of 5'7 ".

The film properties can be found in Table 2 under 6b (invention).

c) The procedure is as under b), but 106 g (2 mol) of acrylonitrile are used. The result is a yellowish oil with an outlet viscosity of 5'50 "in a 6 mm DIN cup and the NH equivalent of 90.

The film properties can be found in Table 2 under 6c (invention).

Example 7

a) A mixture of 58 g (0.25 mol) of pentaethylene hexamine, 47 g (0.25 mol) of tetraethylene pentamine, 37 g (0.25 mol) of triethylene tetramine, 26 g (0.25 mol) of diethylene triamine, 124 g (1, 1 mol) of caprolactam and 0.9 g of p-toluenesulfonic acid is heated to 180-190 ° C. for 6-7 hours with stirring and nitrogen. A yellowish oil with an NH equivalent of 45 is obtained.

The turnover was: approx. 85%.

The film properties can be found in Table 2 under 7a (comparison).

b) 293 g of the reaction mixture according to a) are reacted quantitatively at 60-70 ° C. with 106 g (2 mol) of acrylonitrile. The oily yellowish reaction product has an outlet viscosity of 2'20 "in a 6 mm DIN cup and an NH equivalent of 88.

The film properties can be found in Table 2 under 7b (invention).

Claims (1)

1. A hardener for polyepoxides containing more than one 1,2-epoxide group per molecule based on cyanoethylated polyamide amines of polyadded units of

   A. 1 mole of a polyamine of the formula

   

   wherein p = ₀, n = 2 or 3, m = 0 to 6 and X = NH₂ or
   p=2 or 3, m=0 and X=H;

   B. 0.5-2.3 moles of a saturated lactam and

   C. 0.4-2.8 moles of acrylonitrile, methacrylonitrile or mixtures thereof, characterised in that the polyamine is pentaethylene hexamine.